[jdev] SOCKS5 Bytestream File Transfer problem

[Anthony Ortiz]

Good morning everyone,

Last week I decided to sit down and write a Jabber client in a Java
applet, and I've implemented the basics so far (am able to
digest/plain-text log in, check roster, send/process presence, and
chat.) Now I would like to add File Transfer capabilities,
specifically SOCKS5 Bytestreams
(http://www.jabber.org/jeps/jep-0065.html). I think I am doing
everything right, but for some reason it keeps telling me that it is
unable to find the (SHA1 hashed) host.

I am doing all my testing on my local machine, which is running the
JabberD server as well as acting as a web server.
I am using a PSI client to send the file and my java applet is
receiving. * note : props to the PSI people... good job on the client.
*
I am also aware that an applet can only open a socket connection to
the webserver hosting the applets' webpage, which is why I plan on
implementing the proxy "middleman" protocol later on but for now I
just want to do a direct transfer, so I've temporarily enabled all
socket access in my .java.policy file.

This is basically what I have going on in pseudo java :

* XML STREAM INFO SENT FROM PSI INITIATOR *
<iq xmlns='jabber:client' type='set' to='aortiz at 68.101.84.233/JClient'
id='ab33a' from='venkata at 68.101.84.233/Psi'>
   <query xmlns='http://jabber.org/protocol/bytestreams' mode='tcp'
sid='s5b_8e463861b5e6bc04'>
      <streamhost xmlns='http://jabber.org/protocol/bytestreams'
port='8010' host='192.168.1.100' jid='venkata at 68.101.84.233/Psi'/>
      <fast xmlns='http://affinix.com/jabber/stream'/>
   </query>
</iq>
* END OF STREAM INFO *

* CODE START*
sid = s5b_8e463861b5e6bc04
from = venkata at 68.101.84.233/Psi
to = aortiz at 68.101.84.233/JClient

// using libidn/java/gnu/inet/encoding/Stringprep.java -- too boring
to implement, thk god I found this!
String SocksHost = SHA1(sid + Stringprep.nameprep(from + to)); // HASH
OUTPUT=9134A1B74EB358B866C604B1E1B0DDEE0D664967

host = 192.168.1.100 
port = 8010 
// using http://lightning.prohosting.com/~kirillka/SOCKS/SOCKSLib.html
SOCKS5 library. thk god for this too!
Proxy.setDefaultProxy(host, port);
Socket ss = new SocksSocket(SocksHost, 0);  // <-- Unknown Host Exception

* CODE END *

I'm sure my SHA1 algorithm works since I use it for digest
authentication and I log in fine. Can anyone spot the problem here?
Can someone confirm that my hash of the provided [sid + from + to] is
correct? Can anyone provide some insight or some example code?

Also, the jep--0065 is sort of vague on what should be going on here,
especially where they say that the target MAY have to authenticate
with the proxy. I don't understand what they mean by MAY... either you
do or you don't is what I figure. Are there any documents out there
that can explain this whole process in absolute detail?

Thanks everyone!!

Anthony